The Lorentz polarization term for magnetospheric whistler propagation

摘要: If the particles of a dielectric are arranged in cubic lattice, effective field acting on particle is E + lP/eo, where l = 1/3. The second term Lorentz polarization term. Appleton believed that this should be omitted from magneto-ionic theory, whereas Hartree included it. Various arguments have been presented to prove Appleton's contention zero for plasma. Some proofs considered perturbation individual orbits electrons, but careful consideration these treatments shows they would predict nonzero some velocity distributions. It has also argued ≠ 0 violate causality it can shown only applies frequency limit positive l. Other possess significant limitations, particular being limited rather simpler plasma configurations than exist magnetosphere and weak strengths. theoretical problem more general conditions very difficult thus an appeal experiment results relevant. small whistler-mode propagation. observed lower cutoff frequencies whistlers put low (l ∼ 10−5) maximum value no negative shown, however, < increase ducted Thus upper determined values range −5×10−6 −2×l0−3 by ray tracing model Gaussian cross-section duct realistic magnetospheric corresponding winter night conditions. Cutoffs (normalized equatorial electron gyrofrequency curve fitting ray-traced whistler spectra) found 0.49 0.55 15% enhancement duct. cutoffs −10−4 much better agreement with experimentally assumption (no term). This provides experimental evidence (negative)